Epoxy resin composition for semiconductor sealing

ABSTRACT

An epoxy resin composition for semiconductor sealing, comprising as essential components: 
     (A) an epoxy resin, 
     (B) a phenolic resin curing agent comprising 30-100% by weight, based on the total amount of the phenolic resin curing agent, of a silicone-modified phenolic resin curing agent obtained by reacting a phenolic resin with at least one of silicone compounds represented by the following formulas [I] and [II] ##STR1## wherein ##STR2## A: --R--COOH, ##STR3##  or H, R: a lower alkylene group, 
     10≦N=l+m+n+2≦200, 
     0≦m/N≦0.1, and 5≦N/n≦50, 
     (C) an inorganic filler, and 
     (D) a curing accelerator.

The present invention relates to an epoxy resin composition forsemiconductor sealing, which is excellent in soldering heat resistance,thermal impact resistance and moldability.

Epoxy resins are excellent in heat resistance, electrical properties,mechanical strengths and adhesion, and find wide uses in coatings,adhesives, resins for sealing of electronic parts, resins for laminatedplates and various other applications.

For example, in resin sealing of semiconductor devices (e.g., IC, LSI,transistor and diode), electronic circuits, etc., there are generallyused epoxy resin compositions in view of the properties and cost ofintended products.

In such resin sealing, however, there have been considered problems of(a) increase in package crack caused by temperature cycle and (b)increase in package crack caused by thermal impact of soldering duringsurface mounting, because of changes to larger IC size and smaller andthinner package size. Accordingly, effective measures for solving theseproblems are desired seriously.

For solving the problems, investigations are being made on (1) lowerelastic modulus, (2) lower thermal expansion coefficient, (3) higherimpact strength and (4) lower water absorbability.

With respect to the lower elastic modulus (1), it is said that the useof a silane-modified epoxy resin compound is effective [Japanese PatentApplication Kokai (Laid-Open) No. 73725/1986 and Japanese PatentApplication Kokai (Laid-Open) No. 174222/1987]. However, the adoption ofa lower elastic modulus alone gives lower strength and hence lower heatresistance for soldering, and accordingly it was impossible to obtain agood resin composition for semiconductor sealing.

With respect to the lower thermal expansion coefficient (2), it is saidthat increasing the amount of silica filler used in a resin compositionis effective. However, this approach brings about a problem of viscosityincrease of the resin composition caused by increase in filler amount,and accordingly it was necessary to clear the significant reduction inmoldability.

With respect to the higher impact strength (3), it is said that the useof a biphenyl type epoxy resin or a trifunctional epoxy resin [JapanesePatent Application Kokai (Laid-Open) No. 168620/1986]is effective.However, the use of any of these resins gives reduction in moldability,particularly reduction in thin flash property and mold stainingproperty.

With respect to the lower water absorbability (4), it is said that theuse of a silicone-modified resin or the increase in amount of fillerused is effective. However, any of these approaches has theabove-mentioned drawbacks and is not put into practical application.

The present invention has been made in view of the above situation andis intended to provide an epoxy resin composition for semiconductorsealing, which is satisfactory in all of soldering heat resistance,thermal impact resistance and moldability.

The present inventors made extensive study in order to obtain an epoxyresin composition for semi-conductor sealing, which is free from thedrawbacks of the prior art and has excellent balanced properties. As aresult, it was found that an epoxy resin composition obtained byincorporating into (A) an epoxy resin, (B) a phenolic resin curing agentcomprising 30-100% by weight, based on the total amount of the phenolicresin curing agent, of a silicone-modified phenolic resin curing agentobtained by reacting a phenolic resin with at least one of siliconecompounds represented by the following formulas [I]and [II]capable ofimparting remarkably high toughness and low elasticity withoutsacrifying moldability, ##STR4## wherein ##STR5## A:--R--COOH, ##STR6##or H, R: a lower alkylene group,

10≦N=l+m+n+2≦200,

0≦m/N≦0.1, and 5 ≦N/n≦50,

(C) an inorganic filler and (D) a curing accelerator, and givesufficient improvements in all of moldability, soldering heat resistanceand thermal impact resistance, even to thin and large chip packages. Theabove finding had led to the completion of the present invention.

The first preferable embodiment of the present invention consists of anepoxy resin composition as mentioned above, wherein the epoxy resincomprises 30-100% by weight, based on the total amount of the epoxyresin, of at least one epoxy compound selected from the group consistingof naphthalene type epoxy compounds represented by the following formula[III] and biphenyl type epoxy compounds represented by the followingformula [IV]all effective for obtaining improved impact strength andlower viscosity ##STR7## wherein R:H or CH₃, and the inorganic filler isused in an amount of 70-90% by weight based on the total amount of thecomposition.

The second preferable embodiment of the present invention consists of anepoxy resin composition as mentioned above, wherein the epoxy resincomprises 50-100% by weight, based on the total amount of the epoxyresin, of a mixture of a biphenyl type epoxy resin represented by thefollowing formula [IV] effective for obtaining improved thermal impactresistance and lower viscosity ##STR8## wherein R:H or CH₃, and atrifunctional epoxy resin represented by the following formula [V]effective for obtaining improved heat resistance for soldering ##STR9##wherein R₁ to R₁₁ are each an atom or an atomic group selected fromhydrogen, halogens and alkyl groups.

The epoxy resin used in the present invention as the component (A) canbe any epoxy resin as long as it has at least two epoxy groups in themolecule. As the epoxy resin, there can be cited, for example, bisphenolA type epoxy resins, bisphenol F type epoxy resins, phenol novolac typeepoxy resins, cresol novolac type epoxy resins, alicyclic epoxy resinsand resins obtained by modifying them. These epoxy resins can be usedalone or in admixture of two or more.

Of these epoxy resins, preferable are those having an epoxy equivalentof 150-250 and a softening point of 60-130° C. and containing ionicimpurities such as Na⁺, Cl⁻ and the like in amounts as small aspossible.

The naphthalene type epoxy resin represented by the formula [III]and thebiphenyl type epoxy resin represented by the formula [IV] both used inthe first preferable embodiment of the present invention have aviscosity as low as several centipoises at the molding temperature(165-185° C.) of the present resin composition, and accordingly canreduce the viscosity of the composition significantly. Therefore, theuse of these epoxy resins can significantly increase the amount offiller used in the resin composition, as compared with the usual level.

These epoxy compounds, having a planar structure and being dense inmolecular packing, can allow the resulting resin composition to haveimproved impact strength and excellent thermal impact resistance,soldering heat resistance and moisture resistance after soldering.

However, the epoxy resin comprising these epoxy compounds in a totalamount of 30% by weight or more, is inferior in reactivity andcompatibility with other resins and has low viscosity; therefore, theresin has had a problem of allowing the resulting resin composition tohave reduced moldability, particularly, reduced thin flash property andmold staining property.

The problem, however, could be cleared by using the above-mentionedsilicone-modified phenolic resin in combination.

The naphthalene type epoxy compound represented by the formula [III], orthe biphenyl type epoxy compound represented by the formula [IV], or amixture thereof may be mixed with other epoxy resins; however, theamount of the compound [III] or the compound [IV] or the mixture in thetotal epoxy resin amount is preferably 30% by weight or more.

When the amount is less than 30% by weight, it is difficult to obtainsufficiently low viscosity, low water absorbability and high impactstrength, and the resulting resin composition has relativelyinsufficient soldering heat resistance and fluidity.

When the naphthalene type epoxy resin represented by the formula[III]and the biphenyl type epoxy resin represented by the formula[IV]are used in combination, it is preferable that the former and thelatter be used at a weight ratio of 10/90 to 90/10.

The naphthalene type epoxy compound has high reactivity and givesincreased strength, and accordingly can give improved soldering heatresistance. However, the compound has no sufficient thermal impactresistance and moreover is difficult to handle because it is liquid.

Meanwhile, the biphenyl type epoxy compound has excellent soldering heatresistance and thermal impact resistance and gives no inconvenience inhandling because it is crystalline. However, the compound has somewhatlow reactivity.

Hence, the combined use of the above two compounds can give a resincomposition wherein their drawbacks are supplemented by each other.

The biphenyl type epoxy resin represented by the formula [IV], which isused in the second preferable embodiment of the present invention, has alow viscosity of few centipoises at a molding temperature (165-185° C)and accordingly can significantly reduce the viscosity of the resultingresin composition. The biphenyl type epoxy resin further has a planarstructure and has suf-ficiently dense molecular packing and therefore,can improve the strength and thermal impact resistance of the resultingresin composition. This resin, however, has poor reactivity andcompatibility with other resins and possesses low viscosity andaccordingly, has been inferior in moldability, particularly thin flashproperty and mold staining property.

This problem could be cleared by the combined use with theabove-mentioned silicone-modified phenolic resin.

When the amount of the trifunctional epoxy resin of the formula [V] usedis appropriately controlled, the resulting resin composition can have amaximum resistance to soldering stress. In the formula, R₁, R₂, R₄ toR₇, R₁₀ and R₁₁ are each preferably hydrogen atom, and R₃, R₈ and R₉ areeach preferably methyl group.

The trifunctional epoxy resin, as compared with ordinary phenol novolactype epoxy resins, has a structure wherein motion of the main chain isrestricted; accordingly, has high Tg and excellent heat resistance.

The total amount of the epoxy resins of the formula [IV] and the formula[V] is preferably 50-100% by weight based on the total epoxy resinamount. When it is less than 50% by weight, the resulting resincomposition tends to be insufficient in both or either of soldering heatresistance and fluidity.

The weight ratio of the epoxy resins of the formula [IV] and the formula[V]is preferably [IV]/[V]=10/90 to 90/10. When it is less than 10/90,the resulting resin composition tends to have reduced fluidity andincreased viscosity. When it is more than 90/10, the composition tendsto have reduced resistance to soldering heat.

The silicone-modified phenolic resin curing agent used as the component(B) in the present invention can increase both soldering heat resistanceand thermal impact resistance, and is a very important component. Thephenolic resin as the one raw material for the silicone-modifiedphenolic resin includes, for example, phenol novolac resins, cresolnovolac resins and resins obtained by modifying them, etc. These resinscan be used alone or in admixture of two or more.

Of these phenolic resins, preferable are those which have a hydroxylgroup equivalent of 80-150 and a softening point of 60-120° C. and whichcontain ionic impurities (e.g., Na⁺, Cl⁻) in an amount as small aspossible.

The organopolysiloxane as the other raw material for thesilicone-modified phenolic resin of the present invention has functionalgroups capable of reacting with the above phenolic resin. The functionalgroups include carboxyl group, cyclohexyl type epoxy group, glycidyltype epoxy group and active hydrogen.

The organopolysiloxane is represented by the following formula [I]or[II]: ##STR10## wherein ##STR11## A: --R--COOH, ##STR12## or H, R: alower alkylene group,

10≦N=l+m+n+2≦200,

0≦m/N≦0.1 , and 5≦N/n≦50 .

When N (l+m+n+2) is less than 10, the resulting resin composition hasincreased elastic modulus and decreased strength, and it is difficult tosynthesize a silicone-modified phenolic resin curing agent because anorganopolysiloxane having in the molecule no group reactive with thephenolic resin (i.e., having no group A in the formula [I] or [II]) isformed as a by-product at a higher probability.

When N is larger than 200, the organopoly-siloxane has reducedmiscibility with the phenolic resin, which makes the reaction with thephenolic resin insufficient, invites bleeding of the silicone oil fromthe phenolic resin and resultantly reduces the moldability of theresulting composition greatly.

In the organopolysiloxane of the formula [I] or [II], m/N is preferably0-0.1. When m/N is larger than 0.1, the thermal motion of siloxane chainis suppressed and the Tg of siloxane component is shifted to a highertemperature side; as a result, a lower stress effect is obtained only ina high temperature range and the resulting resin composition has reducedthermal impact resistance.

Moreover, when m/N is larger than 0.1, the synthesis oforganopolysiloxane costs high.

The ratio m/N can take any value as long as it is not larger than 0.1,but is preferably about 0.05. It is because there is no Tg shift of thesiloxane to a higher temperature side, and furthermore because thepresence of side chain functional groups increases the compatibilitywith the phenolic resin and the synthesis of silicone-modified phenolicresin is easy.

Further, 5≦N/n≦50 is preferable.

When N/n is larger than 50, the reactivity between theorganopolysiloxane and the phenolic resin is poor; therefore, there isbleeding of unreacted organopolysiloxane and the resulting resincomposition has reduced moldability. When N/n is smaller than 5, gellingoccurs during the synthesis reaction and it is impossible to obtain asatisfactory silicone-modified phenolic resin.

The amount of the silicone component used for producing asilicone-modified phenolic resin is preferably 10-50 parts by weight per100 parts by weight of the raw material phenolic resin.

When the amount of the silicone component is less than 10 parts byweight, the resulting silicone-modified phenolic resin is insufficientin thermal impact resistance. When the amount is more than 50 parts byweight, the reaction degree of the silicone component is reduced, thereoccurs bleeding of unreacted organo-polysiloxane, and the resultingresin composition has reduced moldability.

As the organopolysiloxane, there is preferred an organopolysiloxanehaving an epoxy group-containing organic group. Such anorganopolysiloxane having an epoxy group-containing organic group can beobtained by subjecting an organohydrogen polysiloxane and an unsaturateddouble bond group-containing epoxy (e.g., allyl glycidyl ether) to anaddition reaction in the presence of chloroplatinic acid as a catalystin an organic solvent.

The silicone-modified phenolic resin can be obtained, for example, bysubjecting an organopolysiloxane and a phenolic resin to a ring-openingaddition reaction in an organic solvent in the presence of at least onecatalyst selected from imidazoles, organic phosphines and tertiaryamines.

In the present invention, the silicone-modified phenolic resin curingagent can be used alone, but may be used in admixture with conventionalphenolic resin curing agent(s). When the silicone-modified phenolicresin curing agent is used as a mixed system, it is necessary that thesystem comprises at least 30% by weight, based on the total systemamount, of the silicone-modified phenolic resin curing agent. When thecontent of the silicone-modified phenolic resin curing agent is lessthan 30% by weight, the resulting resin composition has reduced thermalimpact resistance. It is preferable that the silicone-modified phenolicresin curing agent be used in an amount of at least 50% by weight. Inthis case, any epoxy resin can be used as the component (A) withoutimpairing the object and effect of the present invention.

The compounding ratio of the total epoxy component and the totalphenolic resin component is preferably 70/100 to 100/70 in terms of theratio of epoxy group/phenolic hydroxyl group. When the ratio is lessthan 70/100 or more than 100/70, there occurs reduction in Tg, reductionin hardness when hot, reduction in moisture resistance, etc., and theresulting resin composition is insufficient for use in semiconductorsealing.

When in an ordinary epoxy resin-phenolic resin system there isincorporated a naphthalene type epoxy compound or a biphenyl type epoxycompound or a mixture thereof, the resulting composition has reducedthin flash property. However, when in an epoxy resin/silicone-modifiedphenolic resin system there is incorporated a naphthalene type epoxycompound or a biphenyl type epoxy compound or a mixture thereof as inthe present invention, the low-molecular epoxy compound reacts also withthe phenolic resin having a high polymerization degree owing to thesilicone modification; consequently, bleeding is unlikely to occur andthere arises no reduction in thin flash property.

The inorganic filler used as the component (C) in the present inventionincludes crystalline silica, fused silica, alumina, calcium carbonate,talc, mica, glass fiber, etc. These fillers can be used alone or inadmixture of two or more. Of them, crystalline silica or fused silica isparticularly preferable.

In the embodiment of the present invention wherein the naphthalene typeepoxy compound or the biphenyl type epoxy compound or the mixturethereof is used, the amount of the inorganic filler used is prefer-ably70-90% by weight based on the total resin composition amount. When theamount is less than 70% by weight, the resulting resin composition tendsto have increased thermal expansion coefficient, no sufficiently lowstress and accordingly reduced thermal impact resistance; tends to havehigher water absorbability and accordingly reduced resistance tosoldering heat; and tends to have too low a viscosity and accordinglythin flash and decreased moldability.

When the amount of the inorganic filler used is more than 90% by weight,the resulting resin composition has too high a viscosity, making themolding difficult.

The curing accelerator used as the component (D) in the presentinvention can be any one as long as it can accelerate the reactionbetween epoxy group and phenolic hydroxyl group. There can be widelyused curing accelerators which are generally used in sealing materials.For example, the following compounds can be used alone or in admixtureof two or more; tertiary amines such as BDMA and the like, imidazoles,1,8-diazabicyclo[5,4,0]undecene-7, and organic phosphorus compounds suchas triphenylphosphine and the like.

Into the epoxy resin composition of the present invention there canfurther be incorporated, as necessary, release agents (e.g., wax), flameretardants (e.g., hexabromobenzene, decabromobiphenyl ether, andantimony trioxide), coloring agents (e.g., carbon black, and red ironoxide), silane coupling agents, thermoplastic resins, etc.

The epoxy resin composition for semiconductor sealing according to thepresent invention can be easily produced by a general process. That is,raw materials of given proportions are thoroughly mixed by a mixer orthe like; the mixture is melt-kneaded by rolls, a kneader or the like;the kneaded product is cooled and solidified; and the solid is ground toan appropriate size.

The present invention can provide an epoxy resin composition having highheat resistance, high thermal impact resistance and good moldability,which has been unobtainable with the prior art. This epoxy resincomposition is excellent in cracking resistance and thermal impactresistance when subjected to heat stress by rapid temperature change ata soldering step. Accordingly, the epoxy resin composition of thepresent invention can be suitably used for sealing, coating, insulation,etc. of electronic and electric parts, particularly high integrationlarge thin chip ICs mounted on surface mounting packages and requiring ahigh degree of reliability.

The present invention is described in more detail referring to SynthesisExamples, Examples and Comparative Examples.

SYNTHESIS EXAMPLE I

As shown in Table I-1, 20 parts by weight of an organopolysiloxane (oneof *I-1 to *I-8 shown later) was reacted with 100 parts by weight of aphenol novolac resin in 200 parts by weight of a butanol solvent in thepresence of a catalyst to obtain silicone-modified phenolic resins I(a)to I(h).

EXAMPLE I-1

    ______________________________________                                        Cresol novolac type epoxy resin                                                                    90     parts by weight                                   (epoxy equivalent = 200, soften-                                              ing point = 65° C.)                                                    Brominated phenol novolac                                                                          10     parts by weight                                   type epoxy resin (epoxy                                                       equivalent = 272, softening                                                   point = 75° C., bromine                                                content = 32%)                                                                Silicone-modified phenol novolac                                                                   60     parts by weight                                   resin curing agent I(a)                                                       Fused silica         450    parts by weight                                   Antimony trioxide    25     parts by weight                                   Silane coupling agent                                                                              2      parts by weight                                   Triphenylphosphine   2      parts by weight                                   Carbon black         3      parts by weight                                   Carnauba wax         3      parts by weight                                   ______________________________________                                    

The above materials were mixed thoroughly at room temperature. Themixture was kneaded by a twin roll at 95-100° C. The kneaded product wascooled, crushed and made into tablets to obtain an epoxy resincomposition for semiconductor sealing.

This material was made into a molding using a transfer molding machine(mold temperature=175° C., curing time=2 minutes), whereby the materialwas examined for mold staining and resin flash. The molding wasafter-cured at 175° C. for 8 hours and examined for markability, thermalimpact resistance, soldering moisture resistance and soldering heatresistance. The results are shown in Table I-2.

EXAMPLES I-2 and I-3

Components were compounded in accordance with the recipes shown in TableI-2 and treated in the same manner as in Example I-1 to obtain epoxyresin compositions for semiconductor sealing. These resin compositionswere examined for properties, and the results are shown in Table I-2.

COMPARATIVE EXAMPLES I-1 to I-6

Components were compounded in accordance with the recipes shown in TableI-2 and treated in the same manner as in Example I-1 to obtain epoxyresin composi-tions for semiconductor sealing. These resin compositionswere examined for properties, and the results are shown in Table I-2.##STR13##

                                      TABLE I-1                                   __________________________________________________________________________                           Silicone-                                                                          Silicone-                                                                          Silicone-                                                                          Silicone-                                                                          Silicone-                                                                          Silicone-                                                                          Silicone-                                                                          Silicone-                                  modified                                                                           modified                                                                           modified                                                                           modified                                                                           modified                                                                           modified                                                                           modified                                                                           modified                                   phenolic                                                                           phenolic                                                                           phenolic                                                                           phenolic                                                                           phenolic                                                                           phenolic                                                                           phenolic                                                                           phenolic                                   resin                                                                              resin                                                                              resin                                                                              resin                                                                              resin                                                                              resin                                                                              resin                                                                              resin                                      I(a) I(b) I(c) I(d) I(e) I(f) I(g) I(h)                __________________________________________________________________________    Raw materials                                                                 Phenolic                                                                          Phenol novolac                                                                        (parts by weight)                                                                        100  100  100  100  100  100  100  100                 resin                                                                             resin (OH                                                                     equivalent:105,                                                               softening point:                                                              95° C.)                                                            Silicone                                                                      Organopolysiloxane *I-1                                                                   (parts by weight)                                                                        20                                                     Organopolysiloxane *I-2                                                                   (parts by weight)                                                                             20                                                Organopolysiloxane *I-3                                                                   (parts by weight)    20                                           Organopolysiloxane *I-4                                                                   (parts by weight)                                                 Organopolysiloxane *I-5                                                                   (parts by weight)              20                                 Organopolysiloxane *I-6                                                                   (parts by weight)                   20                            Organopolysiloxane *I-7                                                                   (parts by weight)                        20                       Organopolysiloxane *I-8                                                                   (parts by weight)                             20                  N (polymerization degree of siloxane)                                                                100  180  20   8    220  100  180  20                  m/N (molar fraction of phenol group or                                                               0.05 0.10 0    0    0.05 0.15 0.05 0                   phenylethyl group)                                                            N/n (siloxane polymerization degree/number of                                                        20   30   10   4    44   20   90   4                   functional groups)                                                            Reaction conditions                                                           Kind of solvent        Butanol                                                                            Butanol                                                                            Butanol                                                                            Butanol                                                                            Butanol                                                                            Butanol                                                                            Butanol                                                                            Butanol             Amount of solvent (parts by weight)                                                                  200  200  200  200  200  200  200  200                 Kind of catalyst       DBU  Tri- DBU  Tri- Tri- DBU  DBU  Tri-                                            phenyl-   phenyl-                                                                            phenyl-        phenyl-                                         phos-     phos-                                                                              phos-          phos-                                           phine     phine                                                                              phine          phine               Amount of catalyst (parts by weight)                                                                 2    2    2    2    2    2    2    2                   Reaction temperature (°C.)                                                                    150  150  150  150  150  150  150  150                 Reaction time (hr)     10   20   10   20   20   10   10   20                  Properties                                                                    Hydroxyl group equivalent (g/eq)                                                                     134  128  128  131  131  128  132  132                 Softening point (°C.)                                                                         107  109  105  105  111  112  106  108                 __________________________________________________________________________

                                      TABLE I-2                                   __________________________________________________________________________                   Example           Comparative Example                                         I-1   I-2   I-3   I-1  I-2  I-3  I-4  I-5  I-6                 __________________________________________________________________________    Epoxy Resin                                                                   Cresol novolac type epoxy                                                                    90                                    90                       resin (epoxy equivalent: 200,                                                 softening point: 65° C.)                                               (parts by weight)                                                             Epoxy resin *I-9     90               90        90        90                  (parts by weight)                                                             Epoxy resin *I-10          90    90        90                                 (parts by weight)                                                             Brominated phenol novolac                                                                    10    10    10    10   10   10   10   10   10                  type epoxy resin (epoxy                                                       equivalent: 272, softening point:                                             75° C., bromine content: 32%)                                          (parts by weight)                                                             Phenolic resin curing agent                                                   Silicone-modified phenolic                                                                   60                                                             resin I(a) (parts by weight)                                                  Silicone-modified phenolic                                                                         30                                                       resin I(b) (parts by weight)                                                  Silicone-modified phenolic 50    10                                           resin I(c) (parts by weight)                                                  Silicone-modified phenolic            60                                      resin I(d) (parts by weight)                                                  Silicone-modified phenolic                 50                                 resin I(e) (parts by weight)                                                  Silicone-modified phenolic                      40                            resin I(f) (parts by weight)                                                  Silicone-modified phenolic                           60                       resin I(g) (parts by weight)                                                  Silicone-modified phenolic                                30                  resin I(h) (parts by weight)                                                  Phenol novolac resin 25    10    40        10   15        25                  (OH equivalent: 105, softening                                                point: 95° C.) (parts by weight)                                       Inorganic filler and others                                                   Fused silica (parts by weight)                                                               450               450                                          Antimony trioxide                                                                            25                25                                           (parts by weight)                                                             Silane coupling agent                                                                        2                 2                                            (parts by weight)                                                             Triphenylphosphine                                                                           2                 2                                            (parts by weight)                                                             Carnauba wax   3                 3                                            (parts by weight)                                                             Carbon black   3                 3                                            (parts by weight)                                                             Properties                                                                    Moldability                                                                         Spiral flow (cm)                                                                       ◯                                                                   95  ◯                                                                   80  ◯                                                                   86  ◯                                                                   87 ◯                                                                   99 X 48 ◯                                                                   98 X 42 X 23                      *I-11                                                                         Length of resin                                                                        ◯                                                                   <0.5                                                                              ◯                                                                   <0.5                                                                              ◯                                                                   <0.5                                                                              ◯                                                                   <0.5                                                                             X >5 Δ                                                                         1.9                                                                              ◯                                                                   <0.5                                                                             X 4.3                                                                              ◯                                                                 <0.5                      flash (mm) *I-12                                                              Mold staining                                                                          ◯                                                                   2800                                                                              ◯                                                                   2300                                                                              ◯                                                                   2200                                                                              ◯                                                                   2400                                                                             Δ                                                                         800                                                                              X 70 ◯                                                                   2600                                                                             X 90 ◯                                                                 2500                      (number of shots)                                                             *I-13                                                                         Markability                                                                            ◯                                                                   0   ◯                                                                   1   ◯                                                                   0   ◯                                                                   1  X 36 X 50 ◯                                                                   0  X 43 ◯                                                                 0                         (number of marks                                                              removed) *I-14                                                          Reliability                                                                         Thermal impact                                                                         ◯                                                                   0   ◯                                                                   0   ◯                                                                   1   X 17 Δ                                                                         9  Δ                                                                         10 X 18 Δ                                                                         8  X  15                     resistance (num-                                                              ber of cracked                                                                moldings) *I-15                                                               Average life in                                                                        ◯                                                                   >300                                                                              ◯                                                                   >300                                                                              ◯                                                                   >300                                                                              X 100                                                                              Δ                                                                         220                                                                              Δ                                                                         200                                                                              X 80 Δ                                                                         200                                                                              X  60                     soldering moisture                                                            resistance test                                                               (hr) *I-16                                                                    Soldering heat                                                                         ◯                                                                   2   ◯                                                                   1   ◯                                                                   0   Δ                                                                         11 Δ                                                                         9  Δ                                                                         10 X 14 Δ                                                                         7  X  18                     resistance (num-                                                              ber of cracked                                                                moldings) *I-17                                                         Overall evaluation                                                                           ◯                                                                       ◯                                                                       ◯                                                                       X    X    X    X    X    X                   __________________________________________________________________________     Evaluation methods                                                            *I11 Spiral flow                                                              This is a length of a molding obtained when 20 g of a sample was molded a     a molding temperature of 175° C. at a molding pressure of 7.0 Mpa      for 2 minutes, using a mold for spiral flow measurement.                      *I12 Length of resin flash                                                    There was measured the length of resin flash of the bent portion of the       molding obtained.                                                             *I13 Mold staining                                                            Mold staining was examined by the number of molding shots when the mold       first showed clouding.                                                        *I14 Markability                                                              50 marks were given to 50 moldings of 10th shot; then, a cellophane tape      was applied to each of the moldings; the tape was removed by peeling; and     the number of marks removed was examined. In Table I2, there is shown the     number of peeled marks among the total 50 marks applied.                      *I15 Thermal impact resistance                                                20 same moldings (chip size = 36 mm.sup.2, package thickness = 2.0 mm,        aftercuring = 175° C. × 8 hours) were subjected to a             temperature cycle test (150° C. to -196° C.) consisting of      500 cycles, to examine the thermal impact resistance by the number of         moldings which gave crack(s). In Table I2, there is shown the number of       moldings which gave crack(s).                                                 *I16 Average life in soldering moisture resistance test                       A sealed test sample was treated in steam of 85° C. and 85% R.H.       for 72 hours; the treated test sample was immersed in a solder bath of        240° C. for 10 seconds; the resulting test sample was subjected to     a pressure cooker test (125° C., 100% R.H.) to examine the poor        opening of circuit.                                                           *I17 Soldering heat resistance                                                20 same moldings (chip size = 36 mm.sup.2, package thickness = 2.05 mm)       were treated in steam of 85° C. and 85% R.H. for 72 hours; the         treated moldings were immersed in a solder bath of 240° C. for 10      seconds to examine the soldering heat resistance by the number of molding     which gave crack(s). In Table I2, there is shown the number of moldings       which gave crack(s).                                                     

SYNTHESIS EXAMPLE II

As shown in Table II-1, an organopolysiloxane (one or more of *II-1 to*II-8 shown later) was reacted with a phenol novolac resin (softeningpoint=105° C. OH equivalent=105) in a solvent in the presence of a of acatalyst to obtain silicon-modified phenolic resins II(a) to II(h).

EXAMPLE II-1

    ______________________________________                                        1,6-Dihydroxynaphthalene                                                                             90 parts by weight                                     diglycidyl ether                                                              Brominated bisphenol A type epoxy resin                                                              10 parts by weight                                     (epoxy equivalent = 370, softening                                            point = 65° C., bromine content = 37%)                                 Silicone-modified phenol novolac resin II(a)                                                         70 parts by weight                                     Crushed fused silica   800 parts by weight                                    Antimony trioxide      10 parts by weight                                     Silane coupling agent  2 parts by weight                                      Triphenylphosphine     2 parts by weight                                      Carbon black           3 parts by weight                                      Carnauba wax           3 parts by weight                                      ______________________________________                                    

The above materials were mixed thoroughly at room temperature. Themixture was kneaded by a win roll at 95-100° C. The kneaded product wascooled, crushed and made into tablets to obtain an epoxy resincomposition for semiconductor sealing.

This material was made into a molding using a transfer molding machine(mold temperature=175° C., curing time=2 minutes). The molding wasafter-cured at 175° C. for 8 hours and examined for properties. Theresults are shown in Table II-2.

EXAMPLES II-2 to II-4

The epoxy resin compositions for semiconductor sealing whose compoundingrecipes are shown in Table II-2 were obtained in the same manner as inExample II-1.

These resin compositions were examined for properties, and the resultsare shown in Table II-2.

COMPARATIVE EXAMPLES II-1 to II-6

The epoxy resin compositions for semiconductor seal whose compoundingrecipes are shown in Table II-2 were obtained in the same manner as inExample II-1.

These resin compositions were examined for properties, and the resultsare shown in Table II-2. ##STR14##

                                      TABLE II-1                                  __________________________________________________________________________                            Silicone-                                                                           Silicone-                                                                            Silicone-                                                                           Silicone-                                                                            Silicone-                                                                           Silicone-                                     modified                                                                            modified                                                                             modified                                                                            modified                                                                             modified                                                                            modified                                      phenolic                                                                            phenolic                                                                             phenolic                                                                            phenolic                                                                             phenolic                                                                            phenolic                                      resin II (a)                                                                        resin II (b)                                                                         resin II (c)                                                                        resin II (d)                                                                         resin II                                                                            resin II              __________________________________________________________________________                                                            (f)                   Raw materials                                                                 Phenolic                                                                           Phenol novolac resin (OH equivalent:                                                             100   100    100   100    100   100                   resin                                                                              105, softening point: 105° C.)                                         (parts by weight)                                                        Silicone                                                                      Organopolysiloxane *II-1 (parts by weight)                                                            30           10                                       Organopolysiloxane *II-2 (parts by weight)                                                                  30     20                                       Organopolysiloxane *II-3 (parts by weight) 30                                 Organopolysiloxane *II-4 (parts by weight)        30                          Organopolysiloxane *II-5 (parts by weight)              30                    Organopolysiloxane *II-6 (parts by weight)                                    Organopolysiloxane *II-7 (parts by weight)                                    N (polymerization degree of siloxane)                                                                 100   150    --    8      250   100                   m/N (molar fraction of phenyl group or                                                                0.05  0.10   --    0      0.06  0.30                  phenylethyl group)                                                            N/n (siloxane polymerization degree/number                                                            20    30     --    8      41.6  25                    of functional groups)                                                         Reaction conditions                                                           Kind of solvent         Toluene                                                                             Toluene                                                                              Toluene                                                                             Toluene                                                                              Toluene                                                                             Toluene               Amount of solvent (parts by weight)                                                                   200   200    200   200    250   200                   Kind of catalyst        Triphenyl-                                                                          Triphenyl-                                                                           Triphenyl-                                                                          Triphenyl-                                                                           Triphenyl-                                                                          Triphenyl-                                    phosphine                                                                           phosphine                                                                            phosphine                                                                           phosphine                                                                            phosphine                                                                           phosphine             Amount of catalyst (parts by weight)                                                                  2     2      3     2      2     3                     Reaction temperature (°C.)                                                                     100   100    100   100    100   100                   Reaction time (hr)      5     5      7     5      7     5                     Properties                                                                    Hydroxyl group equivalent (g/eq)                                                                      137   138    140   135    136   140                   Softening point (°C.)                                                                          105   107    110   106    106   108                   __________________________________________________________________________                                                       Silicone-                                                                           Silicone-                                                               modified                                                                            modified                                                                phenolic                                                                            phenolic                                                                resin II                                                                            resin II             __________________________________________________________________________                                                             (h)                                              Raw materials                                                                 Phenolic                                                                           Phenol novolac resin (OH                                                                        100ivalent:                                                                         100                                              resin                                                                              105, softening point: 105° C.)                                         (parts by weight)                                                        Silicone                                                                      Organopolysiloxane *II-1 (parts by weight)                                    Organopolysiloxane *II-2 (parts by weight)                                    Organopolysiloxane *II-3 (parts by weight)                                    Organopolysiloxane *II-4 (parts by weight)                                    Organopolysiloxane *II-5 (parts by weight)                                    Organopolysiloxane *II-6 (parts by                                                                   30ight)                                                Organopolysiloxane *II-7 (parts by                                                                         30ight)                                          N (polymerization degree of                                                                          180oxane)                                                                           15                                               m/N (molar fraction of phenyl group                                                                  0r    0.07                                             phenylethyl group)                                                            N/n (siloxane polymerization                                                                         60gree/number                                                                       3                                                of functional groups)                                                         Reaction conditions                                                           Kind of solvent        Toluene                                                                             Toluene                                          Amount of solvent (parts by                                                                          200ght)                                                                             200                                              Kind of catalyst       Triphenyl-                                                                          Triphenyl-                                                              phosphine                                                                           phosphine                                        Amount of catalyst (parts by                                                                         3eight)                                                                             2                                                Reaction temperature (°C.)                                                                    100   100                                              Reaction time (hr)     5     5                                                Properties                                                                    Hydroxyl group equivalent (g/eq)                                                                     142   137                                              Softening point (°C.)                                                                         110   105                  __________________________________________________________________________

                                      TABLE II-2                                  __________________________________________________________________________                                                        Comparative                                             Example               Example                                                 II-1 II-2  II-3 II-4  II-1 II-2                 __________________________________________________________________________    Epoxy resin                                                                   Naphthalene type epoxy resin *II-8 (parts by weight)                                                        90   90    90   50    90   90                   Epoxy resin *II-9 (parts by weight)           40                              Brominated bisphenol A type epoxy resin (epoxy equivalent:                                                  10   10    10   10    10   10                   370, softening point: 65° C.) (parts by weight)                        Phenolic resin curing agent                                                   Silicone-modified phenol novolac resin II (a) (parts by                                                     70ight)                                         Silicone-modified phenol novolac resin II (b) (parts by                                                          70ight)    30                              Silicone-modified phenol novolac resin II (c) (parts by                                                                70ight)                                                                            10                              Silicone-modified phenol novolac resin II (d) (parts by                                                                           70ight)                   Silicone-modified phenol novolac resin II (e) (parts by                                                                                70ight)              Silicone-modified phenol novolac resin II (f) (parts by weight)               Silicone-modified phenol novolac resin II (g) (parts by weight)               Silicone-modified phenol novolac resin II (h) (parts by weight)               Phenol novolac resin (OH equivalent: 105, softening point:                    105° C.) (parts by weight)                                             Phenolic resin *II-10 (parts by weight)       30                              Filler                                                                        Crushed filler (parts by weight)                                                                            800  800   800        800  800                  Spherical filler (parts by weight)            1000                            Spiral flow (cm) *II-11       95   96    101  92    45   85                   Length of resin flash (mm) *II-12                                                                             0.5                                                                                0.4   0.6                                                                                0.4   0.6                                                                                5.3                Flexural strength (kg/mm.sup.2)/elastic modulus (kg/mm.sup.2)                                               1450/                                                                              1450/ 1430/                                                                              1450/ 1450/                                                                              1510/                                                16.0                                                                               16.2                                                                                15.9                                                                               16.0                                                                                16.0                                                                               15.0               Flexural expansion coefficient (× 10.sup.-5 /°C.)                                                 1.40                                                                               1.41                                                                                1.38                                                                               1.35                                                                                1.50                                                                               1.40              Tg (°C.) *II-15        155  160   152  155   145  149                  Thermal impact resistance (number of cracked moldings) *II-16                                                0    0     0     0    2    2                   Soldering heat resistance (number of cracked moldings) *II-17                                                0    0     1    0     3    2                   Overall evaluation            ◯                                                                      ◯                                                                       ◯                                                                      ◯                                                                       Δ                                                                            X                    __________________________________________________________________________                                               Comparative Example                                                           II-3 II-4 II-5 II-6                __________________________________________________________________________                 Epoxy resin                                                                   Naphthalene type epoxy resin *II-8 (parts by                                                                90ight)                                                                            90   90   80                               Epoxy resin *II-9 (parts by weight)           5                               Brominated bisphenol A type epoxy resin (epoxy                                                              10uivalent:                                                                        10   10   10                               370, softening point: 65° C.) (parts by weight)                        Silicone-modified phenol novolac resin II (a) (parts by                       weight)                                      10                               Silicone-modified phenol novolac resin II (b) (parts by                       weight)                                                                       Silicone-modified phenol novolac resin II (c) (parts by                       weight)                                                                       Silicone-modified phenol novolac resin II (d) (parts by                       weight)                                                                       Silicone-modified phenol novolac resin II (e) (parts by                       weight)                                                                       Silicone-modified phenol novolac resin II (f) (parts by                       weight)                       70                                              Silicone-modified phenol novolac resin II (g) (parts by                       weight)                            70                                         Silicone-modified phenol novolac resin II (h) (parts by                       weight)                                 70                                    Phenol novolac resin (OH equivalent: 105, softening                                                                        50int:                           105° C.) (parts by weight)                                             Phenolic resin *II-10 (parts by weight)                                       Crushed filler (parts by weight)                                                                            800  800  800  800                              Spherical filler (parts by weight)                                            Spiral flow (cm) *II-11       91   89   62   85                               Length of resin flash (mm) *II-12                                                                             0.6                                                                                4.2                                                                                0.5                                                                              >10                              Flexural strength (kg/mm.sup.2)/elastic modulus                               (kg/mm.sup.2) *II-13          1450/                                                                              1520/                                                                              1450/                                                                              1700/                                                            16.1                                                                               15.3                                                                               15.5                                                                               16.5                           Flexural expansion coefficient (× 10.sup.-5 /°C.                 ) *II-14                         1.41                                                                               1.42                                                                               1.40                                                                               1.50                          Tg (°C.) *II-15        155  152  159  158                              Thermal impact resistance (number of cracked moldings)                        *II-16                         5    2    3   10                               Soldering heat resistance (number of cracked moldings)                        *II-17                         0    1    2    2                               Overall evaluation            Δ                                                                            X    Δ                                                                            X                   __________________________________________________________________________     Evaluation methods                                                            *II11 Spiral flow Measured by the same method as for *I11.                    *II12 Length of resin flash Measured by the same method as for *I12.          *II13 Flexural strength and elastic modulus Measured at a span of 100 mm      at a speed of 10 mm/min at room temperature, using a TENSILON flexural        strength tester.                                                              *II14 Thermal expansion coefficient Measured at 25° C. for a sampl     of 15 × 3 × 4 mm, using a thermal expansion coefficient           tester.                                                                       *II15 Tg (glass transition temperature) Measured for a sample of 15           × 3 × 4 mm, using a thermal expansion coefficient tester.         *II16 Thermal impact resistance Measured by the same method as for *I15.      *II17 Soldering heat resistance 20 Moldings (chip size = 36 mm.sup.2,         package thickness = 2.0 mm) were treated in steam of 85° C. and 85     R.H. for 72 hours, and the treated moldings were subjected to VPS (vapor      phase soldering) treatment at 215° C. for 90 seconds to examine th     soldering heat resistance by the number of moldings which gave crack(s). 

SYNTHESIS EXAMPLE III

As shown in Table III-1, an organopolysiloxane (one or two of *II-1 to*III-7 shown later) was reacted with a phenol novolac resin (softeningpoint=105° C., OH equivalent=105) in a solvent in the presence of acatalyst to obtain silicone-modified phenolic resins III(a) to III(h).

EXAMPLE III-1

    ______________________________________                                        3,5,3' , 5'-Tetramethyl-4,4' -                                                                     90     parts by weight                                   dihydroxybiphenyl diglycidyl                                                  ether                                                                         Brominated bisphenol A type                                                                        10     parts by weight                                   epoxy resin (epoxy equivalent =                                               370, softening point = 65° C.,                                         bromine content = 37%)                                                        Silicone-modified phenol                                                                           70     parts by weight                                   novolac resin III(a)                                                          Crushed fused silica 800    parts by weight                                   Antiomony trioxide   10     parts by weight                                   Silane coupling agent                                                                              2      parts by weight                                   Triphenylphosphine   2      parts by weight                                   Carbon black         3      parts by weight                                   Carnauba wax         3      parts by weight                                   ______________________________________                                    

The above materials were mixed thoroughly at room temperature. Themixture was kneaded by a twin roll at 95-100° C. The kneaded product wascooled, crushed and made into tablets to obtain an epoxy resincomposition for semiconductor sealing.

This material was made into a molding using a transfer molding machine(mold temperature=175° C., curing time=2 minutes). The molding wasafter-cured at 175° C. for 8 hours and examined for properties. Theresults are shown in Table III-2.

EXAMPLE III-2

An epoxy resin composition for semiconductor sealing was obtained in thesame manner as in Example III-1 except that the amount of3,5,3',5'-tetramethyl-4,4'-dihydroxybiphenyl diglycidyl ether waschanged from 90 parts by weight to 50 parts by weight and there wasnewly added 35 parts by weight of 4,4'-dihdyroxybiphenyl diglycidylether.

The resin composition was examined for properties, and the results areshown in Table III-2.

EXAMPLES III-3 to III-4

Epoxy resin compositions for semiconductor sealing whose compoundingrecipes are shown in Table III-2 were obtained in the same manner as forExample III-1.

The resin compositions were examined for properties, and the results areshown in Table III-2.

COMPARATIVE EXAMPLES III-1 to III-6

Epoxy resin compositions for semiconductor sealing whose compoundingrecipes are shown in Table III-2 were obtained in the same manner as forExample III-1.

The resin compositions were examined for properties, and the results areshown in Table III-2. ##STR15##

                                      TABLE III-1                                 __________________________________________________________________________                           Silicone-                                                                          Silicone-                                                                          Silicone-                                                                          Silicone-                                                                          Silicone-                                                                          Silicone-                                                                          Silicone-                                                                          Silicone-                                  modified                                                                           modified                                                                           modified                                                                           modified                                                                           modified                                                                           modified                                                                           modified                                                                           modified                                   phenolic                                                                           phenolic                                                                           phenolic                                                                           phenolic                                                                           phenolic                                                                           phenolic                                                                           phenolic                                                                           phenolic                                   resin                                                                              resin                                                                              resin                                                                              resin                                                                              resin                                                                              resin                                                                              resin                                                                              resin                                      III(a)                                                                             III(b)                                                                             III(c)                                                                             III(d)                                                                             III(e)                                                                             III(f)                                                                             III(g)                                                                             III(h)              __________________________________________________________________________    Raw materials                                                                 Phenolic                                                                           Phenol novolac                                                                        (parts by weight)                                                                       100  100  100  100  100  100  100  100                 resin                                                                              resin (OH                                                                     equivalent:                                                                   105, softening                                                                point: 105° C.)                                                   Silicone                                                                      Organopolysiloxane *III-1                                                                  (parts by weight)                                                                       30        10                                           Organopolysiloxane *III-2                                                                  (parts by weight)                                                                            30   20                                           Organopolysiloxane *III-3                                                                  (parts by weight)        30                                      Organopolysiloxane *III-4                                                                  (parts by weight)             30                                 Organopolysiloxane *III-5                                                                  (parts by weight)                  30                            Organopolysiloxane *III-6                                                                  (parts by weight)                       30                       Organopolysiloxane *III-7                                                                  (parts by weight)                            30                  N (polymerization degree of siloxane)                                                                100  160  --   8    236   100 180  17                  m/N (molar fraction of phenyl group or                                                               0.06 0.094                                                                              --   0    0.004                                                                              0.30 0    0.06                phenylethyl group)                                                            N/n (siloxane polymerization degree/number                                                           20   26.7 --   8    33.7 25   60   2.4                 of functional groups)                                                         Reaction conditions                                                           Kind of solvent        Toluene                                                                            Toluene                                                                            Toluene                                                                            Toluene                                                                            Toluene                                                                            Toluene                                                                            Toluene                                                                            Toluene             Amount of solvent (parts by weight)                                                                  200  200  200  230  250  200  200  200                 Kind of catalyst       Tri- Tri- Tri- Tri- Tri- Tri- Tri- Tri-                                       phenyl                                                                             phenyl                                                                             phenyl                                                                             phenyl                                                                             phenyl                                                                             phenyl                                                                             phenyl                                                                             phenyl                                     phos-                                                                              phos-                                                                              phos-                                                                              phos-                                                                              phos-                                                                              phos-                                                                              phos-                                                                              phos-                                      phine                                                                              phine                                                                              phine                                                                              phine                                                                              phine                                                                              phine                                                                              phine                                                                              phine               Amount of catalyst (parts by weight)                                                                 2    2    3    2    2    3    3    2                   Reaction temperature (°C.)                                                                    100  100  100  100  100  100  100  100                 Reaction time (hr)     5    5    7    5    7    5    5    5                   Properties                                                                    Hydroxyl group equivalent (g/eq)                                                                     137  138  140  135  136  140  136  138                 Softening point (°C.)                                                                         105  107  110  106  106  108  111  106                 __________________________________________________________________________

                                      TABLE III-2                                 __________________________________________________________________________                           Example         Comparative Example                                           III-1                                                                             III-2                                                                             III-3                                                                             III-4                                                                             III-1                                                                             III-2                                                                             III-3                                                                             III-4                                                                             III-5                                                                             III-6              __________________________________________________________________________    Epoxy resin                                                                   3,5,3' ,5' -Tetramethyl-4,4' -                                                              (parts by weight)                                                                      90  50  20  30  90  90  90  90  90  80                 dihydroxybiphenyl diglycidyl                                                  ether *III-8                                                                  4,4'-Dihydroxybiphenyl                                                                      (parts by weight)                                                                          35  60  30                                         diglycidyl ether *III-9                                                       Epoxy resin *III-10                                                                         (parts by weight)    40                      5                  Brominated bisphenol A type                                                                 (parts by weight)                                                                      10  10  10  10  10  10  10  10  10  10                 epoxy resin (epoxy                                                            equivalent:                                                                   370, softening point: 65° C.)                                          Phenolic resin curing agent                                                   Silicone-modified                                                                       III(a)                                                                            (parts by weight)                                                                      70  70                              10                 phenol novolac                                                                resin                                                                         Silicone-modified                                                                       III(b)                                                                            "                70                                             phenol novolac                                                                resin                                                                         Silicone-modified                                                                       III(c)                                                                            "                    50                                         phenol novolac                                                                resin                                                                         Silicone-modified                                                                       III(d)                                                                            "                        70                                     phenol novolac                                                                resin                                                                         Silicone-modified                                                                       III(e)                                                                            "                            70                                 phenol novolac                                                                resin                                                                         Silicone-modified                                                                       III(f)                                                                            "                                70                             phenol novolac                                                                resin                                                                         Silicone-modified                                                                       III(g)                                                                            "                                    70                         phenol novolac                                                                resin                                                                         Silicone-modified                                                                       III(h)                                                                            "                                        70                     phenol novolac                                                                resin                                                                         Phenolic novolac resin (OH                                                                  (parts by weight)                            50                 equivalent: 105,                                                              softening point:                                                              (105° C.)                                                              Phenolic resin *III-11                                                                      (parts by weight)    20                                         Filler                                                                        Crushed filler                                                                              (parts by weight)                                                                      800 800 800     800 800 800 800 800 800                Spherical filler                                                                            (parts by weight)    1000                                       Spiral flow (cm) *III-12                                                                             97  96  102 92  45  85  91  91  62  85                 Length of resin flash (mm)                                                                           0.5 0.4 0.6 0.5 0.6 5.3 0.6 4.2 0.5 >10                *III-13                                                                       Flexural strength (kg/mm.sup.2)/                                                                     1450/                                                                             1420/                                                                             1420/                                                                             1450/                                                                             1440/                                                                             1510/                                                                             1450/                                                                             1520/                                                                             1490/                                                                             1690/              elastic modulus        15.5                                                                              16.0                                                                              15.9                                                                              16.0                                                                              16.0                                                                              15.0                                                                              16.1                                                                              15.3                                                                              15.5                                                                              16.5               (kg/mm.sup.2) *III-14                                                         Thermal expansion      1.42                                                                              1.41                                                                              1.40                                                                              1.35                                                                              1.50                                                                              1.45                                                                              1.41                                                                              1.42                                                                              1.40                                                                              1.50               coefficient (× 10.sup.-5 /°C.)                                   *III-15                                                                       Tg (°C.) *III-16                                                                              155 159 152 195 145 149 154 152 159 158                Thermal impact resistance                                                                            0   0   0   0   2   2   5   2   4   10                 (number of cracked                                                            moldings) *III-17                                                             Soldering heat resistance                                                                            1   1   1   0   3   2   0   1   2   2                  (number of cracked                                                            moldings) *III-18                                                             Overall evaluation     ◯                                                                     ◯                                                                     ◯                                                                     ◯                                                                     Δ                                                                           X   Δ                                                                           X   Δ                                                                           X                  __________________________________________________________________________      Evaluation methods                                                           *III12 Spiral flow                                                            Measured by the same method as for *I11.                                      *III13 Length of resin flash                                                  Measured by the same method as for *I12.                                      *III14 Flexural strength and elastic modulus                                  Measured by the same method as for *II13.                                     *III15 Thermal expansion coefficient                                          Measured by the same method as for *II14.                                     *III16  Tg (glass transition temperature)                                     Measured by the same method as for *II15.                                     *III17 Thermal impact resistance                                              Measured by the same method as for *I15.                                      *III18 Soldering heat resistance                                              Measured by the same method as for *II17.                                

SYNTHESIS EXAMPLE IV

As shown in Tale IV-1, an organopolysiloxane (one or two of *IV-1 to*IV-7 shown later) was reacted with a phenol novolac resin (softeningpoint=105° C., OH equivalent=105) in a solvent in the presence of acatalyst to obtain silicone-modified phenolic resins IV(a) to IV(h).

EXAMPLE IV-b 1

    ______________________________________                                        Naphthalene type epoxy compound                                                                   50      parts by weight                                   Biphenyl type epoxy compound A                                                                    50      parts by weight                                   Brominated bisphenol A type                                                                       10      parts by weight                                   epoxy resin (epoxy equivalent =                                               370, softening point = 65° C.,                                         bromine content = 37%                                                         Silicone-modified phenol                                                                          70      parts by weight                                   novolac resin IV(a)                                                           Crushed fused silica                                                                              800     parts by weight                                   Antimony trioxide   10      parts by weight                                   Silane coupling agent                                                                             2       parts by weight                                   Triphenylphosphine  2       parts by weight                                   Carbon black        3       parts by weight                                   Carnauba wax        3       parts by weight                                   ______________________________________                                    

The above materials were mixed thoroughly at room temperature. Themixture was kneaded by a twin roll at 95-100° C. The kneaded product wascooled, crushed and made into tablets to obtain an epoxy resincomposition for semiconductor sealing.

This material was made into a molding using a transfer molding machine(mold temperature=175° C., curing time =2 minutes). The molding wasafter-cured at 175° C. for 8 hours and examined for properties. Theresults are shown in Table IV-2.

EXAMPLES IV-2 to IV-4

Epoxy resin compositions whose compounding recipes are shown in TableIV-2 were obtained in the same manner as in Example IV-1.

These resin compositions were measured for properties, and the resultsare shown in Table IV-2.

COMPARATIVE EXAMPLES IV-b 1 to IV-6

Epoxy resin compositions whose compounding recipes are shown in TableIV-2 were obtained in the same manner as in Example IV-1.

These resin compositions were measured for properties, and the resultsare shown in Table IV-2. ##STR16##

                                      TABLE IV-1                                  __________________________________________________________________________                   Silicone-                                                                           Silicone-                                                                           Silicone-                                                                           Silicone-                                                                           Silicone-                                                                           Silicone-                                                                           Silicone-                                                                           Silicone-                           modified                                                                            modified                                                                            modified                                                                            modified                                                                            modified                                                                            modified                                                                            modified                                                                            modified                            phenolic                                                                            phenolic                                                                            phenolic                                                                            phenolic                                                                            phenolic                                                                            phenolic                                                                            phenolic                                                                            phenolic                            resin IV(a)                                                                         resin IV(b)                                                                         resin IV(c)                                                                         resin IV(d)                                                                         resin IV(e)                                                                         resin IV(f)                                                                         resin                                                                               resin                __________________________________________________________________________                                                             IV(h)                Raw materials                                                                 Phenolic resin                                                                Phenol novolac resin                                                                         100   100   100   100   100   100   100   100                  (OH equivalent: 105, softening                                                point: 105° C.)                                                        (parts by weight)                                                             Silicone                                                                      Organopolysiloxane *IV-1                                                                     30           10                                                (parts by weight)                                                             Organopolysiloxane *IV-2                                                                           30     20                                                (parts by weight)                                                             Organopolysiloxane *IV-3          30                                          (parts by weight)                                                             Organopolysiloxane *IV-4               30                                     (parts by weight)                                                             Organopolysiloxane *IV-5                     30                               (parts by weight)                                                             Organopolysiloxane *IV-6                            30                        (parts by weight)                                                             Organopolysiloxane *IV-7                                 30                   (parts by weight)                                                             N (polymerization degree of                                                                  100   150   --     9    250   100   180   16                   siloxane)                                                                     m/N (molar fraction of phenyl                                                                0.05  0.1   --     0    0.05  0.30   0    0.06                 group or phenylethyl group)                                                   N/n (siloxane polymerization                                                                 14.3  30    --     9    41.6  25     60   2.7                  degree/number of functional                                                   groups)                                                                       Reaction conditions                                                           Kind of solvent                                                                              Toluene                                                                             Toluene                                                                             Toluene                                                                             Toluene                                                                             Toluene                                                                             Toluene                                                                             Toluene                                                                             Toluene              Amount of solvent                                                                            200   200   200   200   250   200   200   200                  (parts by weight)                                                             Kind of catalyst                                                                             Triphenyl-                                                                          Triphenyl-                                                                          Triphenyl-                                                                          Triphenyl-                                                                          Triphenyl-                                                                          Triphenyl-                                                                          Triphenyl-                                                                          Triphenyl-                          phosphine                                                                           phosphine                                                                           phosphine                                                                           phosphine                                                                           phosphine                                                                           phosphine                                                                           phosphine                                                                           phosphine            Amount of catalyst                                                                           2     2      3     2    2     3.5    3    2.5                  (parts by weight)                                                             Reaction temperature (°C.)                                                            100   100   100   100   100   100   100   100                  Reaction time (hr)                                                                           5     5      7     7    7     5      5    5                    Properties                                                                    Hydroxyl group equivalent                                                                    136   138   138   135   136   140   140   137                  (g/eq)                                                                        Softening point (°C.)                                                                 104   107   110   106   105   108   110   106                  __________________________________________________________________________

                                      TABLE IV-2                                  __________________________________________________________________________                           Example         Comparative Example                                           IV-1                                                                              IV-2                                                                              IV-3                                                                              IV-4                                                                              IV-1                                                                              IV-2                                                                              IV-3                                                                              IV-4                                                                              IV-5                                                                              IV-6               __________________________________________________________________________    Epoxy resin                                                                   Naphthalene type epoxy compound *IV-8                                                                50  50  30  25  50  50  50  50  50  40                 (parts by weight)                                                             Biphenyl type epoxy compound A *IV-9                                                                 50      50  10  20  20  20  20  20                     (parts by weight)                                                             Biphenyl type epoxy compound B *IV-10                                                                    40  20  20  30  30  30  30  30  40                 (parts by weight)                                                             Epoxy resin *IV-11 (parts by weight)                                                                             40                       5                 Brominated bisphenol A type epoxy resin (epoxy                                                       10  10  10  10  10  10  10  10  10  10                 equivalent: 370, softening point: 65° C.)                              (parts by weight)                                                             Phenolic resin curing agent                                                   Silicone-modified phenol novolac resin IV(a)                                                         70                                  10                 (parts by weight)                                                             Silicone-modified phenol novolac resin IV(b)                                                             70      30                                         (parts by weight)                                                             Silicone-modified phenol novolac resin IV(c)                                                                 70  10                                         (parts by weight)                                                             Silicone-modified phenol novolac resin IV(d)                                                                         70                                     (parts by weight)                                                             Silicone-modified phenol novolac resin IV(e)                                                                             70                                 (parts by weight)                                                             Silicone-modified phenol novolac resin IV(f)   70                             (parts by weight)                                                             Silicone-modified phenol novolac resin IV(g)       70                         (parts by weight)                                                             Silicone-modified phenol novolac resin IV(h)           70                     (parts by weight)                                                             Phenol novolac resin (OH equivalent: 105,                  50                 softening point: 105° C.) (parts by weight)                            Phenolic resin *IV-12 (parts by weight)                                                                          30                                         Filler                                                                        Crushed filler (parts by weight)                                                                     800 800 800     800 800 800 800 800 800                Spherical filler (parts by weight) 1000                                       Spiral flow (cm) *IV-13                                                                              95  96  101 99  45  85  90  89  60  85                 Length of resin flash (mm) *IV-14                                                                    0.5 0.4 0.4 0.4 0.6 5.3 0.6 5.0 0.5 >10                Flexural strength (kg/mm.sup.2)/elastic modulus                                                      1400/                                                                             1420/                                                                             1430/                                                                             1450/                                                                             1450/                                                                             1510/                                                                             1450/                                                                             1520/                                                                             1490/                                                                             1700/              (kg/mm.sup.2) *IV-15   16.0                                                                              16.2                                                                              15.9                                                                              16.0                                                                              15.5                                                                              15.8                                                                              16.1                                                                              15.3                                                                              15.5                                                                              16.5               Thermal expansion coefficient (10.sup.-5 /°C.) *IV-16                                          1.40                                                                              1.41                                                                              1.38                                                                              1.35                                                                              1.50                                                                              1.38                                                                              1.41                                                                              1.42                                                                              1.40                                                                              1.45              Tg (°C.) *IV-17 155 160 152 155 145 149 156 152 159 158                Thermal impact resistance (number of cracked                                                          0   0   0   0   3   4   5   2   4  20                 moldings) *IV-18                                                              Soldering heat resistance (number of cracked                                                          0   0   1   0   4   4   0   1   2   2                 moldings) *IV-19                                                              Overall evaluation     ◯                                                                     ◯                                                                     ◯                                                                     ◯                                                                     Δ                                                                           X   Δ                                                                           X   Δ                                                                           X                  __________________________________________________________________________     Evaluation methods                                                            *IV13 Spiral flow                                                             Measured by the same method as for *I11.                                      *IV14 Length of resin flash                                                   Measured by the same method as for *I12.                                      *IV15 Flexural strength and elastic modulus                                   Measured by the same method as for *II13.                                     *IV16 Thermal expansion coefficient                                           Measured by the same method as for *II14.                                     *IV17 Tg (glass transition temperature)                                       Measured by the same method as for *II15.                                     *IV18 Thermal impact resistance                                               Measured by the same method as for *I15 except that the number of cycles      was increased to 1,000.                                                       *IV19 Soldering heat resistance                                               20 Moldings (chip size = 36 mm.sup.2, package thickness = 2.0 mm) were        treated in steam of 85° C. and 85% R.H. for 72 hours, and the          resulting moldings were subjected to an infrared reflow treatment at          240° C. to examine the soldering heat resistance by the number of      moldings which gave crack(s).                                            

SYNTHESIS EXAMPLE V

As shown in Table V-1, an organopolysiloxane (one or two of *V-1 to *V-7shown later) was reacted with a phenol novolac resin (softeningpoint=105° C., OH equivalent=105) in a solvent in the presence of acatalyst to obtain silicone-modified phenolic resins V(a) to V(h).

EXAMPLE V-1

    ______________________________________                                        Biphenyl type epoxy resin A *V-8                                                                     40 parts by weight                                     Trifunctional epoxy resin *V-10                                                                      50 parts by weight                                     Brominated bisphenol A type epoxy resin                                                              10 parts by weight                                     (epoxy equivalent = 370, softening point =                                    65° C., bromine content = 37%)                                         Silicone-modified phenol                                                                             70 parts by weight                                     novolac resin V(a)                                                            Crushed fused silica   500 parts by weight                                    Antimony trioxide      10 parts by weight                                     Silane coupling agent  2 parts by weight                                      Triphenylphosphine     2 parts by weight                                      Carbon black           3 parts by weight                                      Carnauba wax           3 parts by weight                                      ______________________________________                                    

The above materials were mixed thoroughly at room temperature. Themixture was kneaded by a twin roll at 95-100° C. The kneaded product wascooled, crushed and made into tablets to obtain an epoxy resincomposition for semiconductor sealing.

This material was made into a molding using a transfer molding machine(mold temperature=175° C., curing time=2 minutes). The molding wasafter-cured at 175° C. for 8 hours and examined for properties. Theresults are shown in Table V-2.

EXAMPLE V-2

An epoxy resin composition for semiconductor sealing was obtained in thesame manner as in Example V-1 except that the biphenyl type epoxy resinA was changed to a biphenyl type epoxy resin B (*V-9) and thesilicone-modified phenol novolac resin V(a) was changed to asilicone-modified phenol novolac resin V(b).

The resin composition was examined for properties, and the results areshown in Table V-2.

EXAMPLE V-3

An epoxy resin composition for semiconductor sealing whose compoundingrecipe is shown in Table V-2, was obtained in the same manner as inExample V-1.

The resin composition was examined for properties, and the results areshown in Table V-2.

COMPARATIVE EXAMPLE V-1 to V-6

Epoxy resin compositions for semiconductor sealing whose compoundingrecipes are shown in Table V-2, were obtained in the same manner as inExample V-1.

The resin compositions were examined for properties, and the results areshown in Table V-2. ##STR17##

                                      TABLE V-1                                   __________________________________________________________________________                            Silicone-                                                                           Silicone-                                                                            Silicone-                                                                           Silicone-                                                                            Silicone-                                                                           Silicone-                                     modified                                                                            modified                                                                             modified                                                                            modified                                                                             modified                                                                            modified                                      phenolic                                                                            phenolic                                                                             phenolic                                                                            phenolic                                                                             phenolic                                                                            phenolic                                      resin V(a)                                                                          resin V(b)                                                                           resin V(c)                                                                          resin V(d)                                                                           resin                                                                               resin                 __________________________________________________________________________                                                            V(f)                  Raw materials                                                                 Phenolic                                                                           Phenol novolac resin (OH equivalent:                                                             100   100    100   100    100   100                   resin                                                                              105, softening point: 105° C.)                                         (parts by weight)                                                        Silicone                                                                      Organopolysiloxane *V-1 (parts by weight)                                                             30           10                                       Organopolysiloxane *V-2 (parts by weight)                                                                   30     20                                       Organopolysiloxane *V-3 (parts by weight)  30                                 Organopolysiloxane *V-4 (parts by weight)         30                          Organopolysiloxane *V-5 (parts by weight)               30                    Organopolysiloxane *V-6 (parts by weight)                                     Organopolysiloxane *V-7 (parts by weight)                                     N (polymerization degree of siloxane)                                                                 100   160    --    8      250   100                   m/N (molar fraction of phenyl group or                                                                0.06  0.094  --    0      0.06  0.30                  phenylethyl group)                                                            N/n (siloxane polymerization degree/number                                                            20    26.7   --    8      35.7  25                    of functional groups)                                                         Reaction conditions                                                           Kind of solvent          Toluene                                                                            Toluene                                                                              Toluene                                                                             Toluene                                                                              Toluene                                                                             Toluene               Amount of solvent (parts by weight)                                                                   200   200    200   230    250   200                   Kind of catalyst        Triphenyl-                                                                          Triphenyl-                                                                           Triphenyl-                                                                          Triphenyl-                                                                           Triphenyl-                                                                          Triphenyl-                                    phosphine                                                                           phosphine                                                                            phosphine                                                                           phosphine                                                                            phosphine                                                                           phosphine             Amount of catalyst (parts by weight)                                                                  3     3      3     3      3     3                     Reaction temperature (°C.)                                                                     100   100    100   100    100   100                   Reaction time (hr)      5     5      7     5      7     5                     Properties                                                                    Hydroxyl group equivalent (g/eq)                                                                      137   138    139   138    136   140                   Softening point (°C.)                                                                          106   107    110   107    106   108                   __________________________________________________________________________                                                       Silicone-                                                                           Silicone-                                                               modified                                                                            modified                                                                phenolic                                                                            phenolic                                                                resin                                                                               resin                __________________________________________________________________________                                                             V(h)                                             Raw materials                                                                 Phenolic                                                                           Phenol novolac resin (OH                                                                        100ivalent:                                                                         100                                              resin                                                                              105, softening point: 105° C.)                                         (parts by weight)                                                        Silicone                                                                      Organopolysiloxane *V-1 (parts by weight)                                     Organopolysiloxane *V-2 (parts by weight)                                     Organopolysiloxane *V-3 (parts by weight)                                     Organopolysiloxane *V-4 (parts by weight)                                     Organopolysiloxane *V-5 (parts by weight)                                     Organopolysiloxane *V-6 (parts by                                                                    30ight)                                                Organopolysiloxane *V-7 (parts by                                                                          30ight)                                          N (polymerization degree of                                                                          180oxane)                                                                           15                                               m/N (molar fraction of phenyl group                                                                  0r    0.07                                             phenylethyl group)                                                            N/n (siloxane polymerization                                                                         60gree/number                                                                       2.5                                              of functional groups)                                                         Reaction conditions                                                           Kind of solvent        Toluene                                                                             Toluene                                          Amount of solvent (parts by                                                                          200ght)                                                                             200                                              Kind of catalyst       Triphenyl-                                                                          Triphenyl-                                                              phosphine                                                                           phosphine                                        Amount of catalyst (parts by                                                                         3eight)                                                                             3                                                Reaction temperature (°C.)                                                                    100   100                                              Reaction time (hr)     5     5                                                Properties                                                                    Hydroxyl group equivalent (g/eq)                                                                     136   138                                              Softening point (°C.)                                                                         111   106                  __________________________________________________________________________

                                      TABLE V-2                                   __________________________________________________________________________                                  Example  Comparative Example                                                  V-1                                                                              V-2                                                                              V-3                                                                              V-1                                                                              V-2                                                                              V-3                                                                              V-4                                                                              V-5                                                                              V-6                     __________________________________________________________________________    Composition                                                                   Biphenyl type epoxy resin A *V-8 (parts by weight)                                                          40    30 40 40 40 40 40 40                      Biphenyl type epoxy resin B *V-9 (parts by weight)                                                             50 15                                        Trifunctional epoxy resin *V-10 (parts by weight)                                                           50 50 50 50 50 50 50 50 50                      o-Cresol novolac epoxy resin (epoxy equivalent: 205,                                                               5                                        softening point: 70° C.) (parts by weight)                             Brominated bisphenol A type epoxy resin (epoxy equivalent:                                                  10 10 10 10 10 10 10 10 10                      370, softening point: 65° C.) (parts by weight)                        Silicone-modified phenol novolac resin V(a) (parts by weight)                                               70                      15                      Silicone-modified phenol novolac resin V(b) (parts by weight)                                                  70                                           Silicone-modified phenol novolac resin V(c) (parts by weight)                                                     65                                        Silicone-modified phenol novolac resin V(d) (parts by weight)                                                        70                                     Silicone-modified phenol novolac resin V(e)  (parts by weight)                                                          70                                  Silicone-modified phenol novolac resin V(f) (parts by weight)                                                              70                               Silicone-modified phenol novolac resin V(g) (parts by weight)                                                                 70                            Silicone-modified phenol novolac resin V (h) (parts by weight)                                                                   70                         Phenol novolac resin (OH equivalent: 105, softening                                                                5                40                      point: 110° C.) (parts by weight)                                      Properties                                                                    Spiral flow (cm) *V-11        90 95 98 60 95 90 94 54 95                      Length of resin flash (mm) *V-12                                                                            0.5                                                                              0.4                                                                              0.3                                                                              0.6                                                                              5.0                                                                              0.5                                                                              5.2                                                                              0.4                                                                              5.2                     Mold staining *V-13           ◯                                                                    ◯                                                                    ◯                                                                    ◯                                                                    X  ◯                                                                    X  ◯                                                                    X                       Koka type flow viscosity (poises) *V-14                                                                     231                                                                              230                                                                              245                                                                              410                                                                              221                                                                              220                                                                              230                                                                              415                                                                              220                     Thermal impact resistance (number of cracked moldings) *V-15                                                 0  0  0  3  4  5  2  4 15                      Soldering heat resistance (number of cracked moldings) *V-16                                                 0  1  0  4  4  0  1  2  2                      Overall evaluation            ◯                                                                    ◯                                                                    ◯                                                                    Δ                                                                          X  Δ                                                                          X  Δ                                                                          X                       __________________________________________________________________________     Evaluation methods                                                            *V11 Spiral flow                                                              Measured by the same method as for *I11.                                      *V12 Length of resin flash                                                    Measured by the same method as for *I12.                                      *V13 Mold staining                                                            Mold staining after 1,000 shots of molding was examined visually.             *V14 Koka type flow viscosity                                                 A Koka type flow viscosity (poises) at 175° C.                         *V15 Thermal impact resistance                                                Measured by the same method as for *I15.                                      *V16 Soldering heat resistance                                                Measured by the same method as for *II17.                                

We claim:
 1. An epoxy resin composition for semiconductor sealing,comprising an essential components: (A) an epoxy resin comprising30-100% by weight, based on the total amount of the epoxy resin, of atleast one epoxy compound selected from the group consisting ofnaphthalene epoxy compounds represented by the following formula andbiphenyl epoxy compounds represented by the following formula: ##STR18##wherein R is H or CH₃, (B) a phenolic resin curing agent comprising30-100% by weight, based on the total amount of the phenolic resincuring agent, of a silicone-modified phenolic resin curing agentobtained by reacting a phenolic resin with at least one of siliconecompounds represented by the following formulas and: ##STR19## wherein##STR20## A is --R--COOH, ##STR21## or H, R is a lower alkylene group,1≦N=1+m+n+2≦200, 0≦m/N≦0.1, and 5≦N/n≦50, (C) 70-90% by weight of aninorganic filler based on the total weight of the composition, and (D) acuring accelerator.
 2. An epoxy resin composition for semiconductorsealing, comprising as essential components:(A) an epoxy resincomprising 50-100% by weight, based on the total amount of the epoxyresin, of a mixture of a biphenyl epoxy resin represented by thefollowing formula: ##STR22## wherein R:H or CH₃, and a trifunctionalepoxy resin represented by the following formula: ##STR23## wherein R₁to R₁₁ are each an atom or atomic group selected from hydrogen, halogensor alkyl groups, (B) a phenolic resin curing agent comprising 30-100% byweight, based on the total amount of the phenolic resin curing agent, ofa silicone-modified phenolic resin curing agent obtained by reacting aphenolic resin with at least one of silicone compounds represented bythe following formulas and: ##STR24## wherein ##STR25## A is --R--COOH,##STR26## or H, R is a lower alkylene group,1≦ N=l+m+n+2≦200, 0≦m/N≦0.1,and 5≦N/n≦50, (C) an inorganic filler, and (D) a curing accelerator. 3.An epoxy resin composition according to claim 2, wherein in the formulasand representing the silicone compounds, ##STR27##
 4. An epoxy resincomposition according to claim 2 wherein the phenolic resin curing agentcomprises the silicone-modified phenolic resin curing agent in an amountof 50-100% by weight based on the total amount of the phenolic resincuring agent.
 5. An epoxy composition according to claim 2 wherein theepoxy resin (A) has an epoxy equivalent of 150-250 and a softening pointof 60-130° C. and is selected from the group consisting of bisphenol Aepoxy resins, bisphenol F epoxy resins, phenol novolac epoxy resins,cresol novolac epoxy resins and alicyclic epoxy resins.
 6. An epoxyresin composition according to claim 2, wherein the phenolic rein has ahydroxyl group equivalent of 80-150 and a softening point of 60-120° C.and is selected from the group consisting of phenol novolac resins,cresol novolac resins and resins obtained by modifying them.
 7. An epoxyresin composition according to claim 2, wherein the silicone-modifiedphenolic resin curing agent is obtained by reacting 100 parts by weightof the phenolic resin with 10-50 parts by weight of at least one of thesilicone compounds.
 8. An epoxy resin composition according to claim 2,wherein the epoxy resin (A) and the phenolic resin curing agent (B) arecompounded at a ratio of 70/100 to 100/70 in terms of epoxygroup/phenolic hydroxyl group.
 9. An epoxy resin composition accordingto claim 2, wherein the inorganic filler (C) is selected from the groupconsisting of crystalline silica, fused silica, alumina, calciumcarbonate, talc, mica and glass fiber.
 10. An epoxy resin compositionaccording to claim 2, wherein the curing accelerator (D) is selectedfrom the group consisting of tertiary amines, imidazoles,1,8-diazabicyclo[5.5.0]undecene-7 and organophophorus compounds.
 11. Anepoxy resin composition according to claim 1, wherein the epoxy resin(A) comprises the naphthalene epoxy compound and the biphenyl epoxycompound at a weight ratio of 10/90 to 90/10.
 12. An epoxy resincomposition according to claim 2, wherein the epoxy resin (A) comprisesthe biphenyl epoxy compound and the trifunctional epoxy compound at aweight ratio of 10/90 to 90/10.
 13. An epoxy resin composition accordingto claim 1, wherein in the formulas [I] and [II] representing thesilicone compounds, ##STR28##
 14. An epoxy resin composition accordingto claim 1, wherein the phenolic resin curing agent comprises thesilicone-modified phenolic resin curing agent in an amount of 50-100% byweight based on the total amount of the phenolic resin curing agent. 15.An epoxy resin composition according to claim 1, wherein the epoxy resin(A) has an epoxy equivalent of 150-250 and a softening point of 60-130°C. and is selected from the group consisting of bisphenol A epoxyresins, bisphenol F epoxy resins, phenol novolac epoxy resins, cresolnovolac epoxy resins and alicyclic epoxy.
 16. An epoxy resin compositionaccording to claim 2, wherein in the formula [V]representing thetrifunctional epoxy resin, R₁, R₂, R₄ to R₇, R₁₀ and R₁₁ are eachhydrogen atom, and R₃, R₈ and R₉ are each methyl group.
 17. An epoxyresin composition according to claim 1, wherein the phenolic resin has ahydroxyl group equivalent of 80-150 and a softening point of 60-120° C.and is selected from the group consisting of phenol novolac resins,cresol novolac resins and resins obtained by modifying them.
 18. Anepoxy resin composition according to claim 1, wherein thesilicone-modified phenolic resin curing agent is obtained by reacting100 parts by weight of the phenolic resin with 10-50 parts by weight ofat least one of the silicone compounds.
 19. An epoxy resin compositionaccording to claim 1, wherein the epoxy resin (A) and the phenolic resincuring agent (B) are compounded at a ratio of 70/100 to 100/70 in termsof epoxy group/phenolic hydroxyl group.
 20. An epoxy resin compositionaccording to claim 1, wherein the inorganic filler (C) is selected fromthe group consisting of crystalline silica, fused silica, alumina,calcium carbonate, talc, mica and glass fiber.
 21. An epoxy resincomposition according to claim 1, wherein the curing accelerator (D) isselected from the group consisting of tertiary amines, imidazoles,1,8-diazabicyclo[5.4.0]undecene-7 and organophosphorus compounds.
 22. Anepoxy resin composition for semiconductor sealing, consistingessentially of:(A) an epoxy resin having either of the followingstructures: ##STR29## wherein R is H or CH₃, (B) a phenolic resin curingagent having either of the following formulas: ##STR30## wherein##STR31## A is --R--COOH, ##STR32## or H, R is lower alkylene group,1≦N=l+m+n+2≦200, 0≦m/N≦0.1, and 5≦N/n≦50, (C) an inorganic filler, and (D)a curing accelerator.